Methods and apparatus for mitigating interference in aggressive form factor designs

ABSTRACT

Methods and apparatus for mitigation of radio interference between two or more wireless concurrently operating interfaces in a wireless device having an aggressive form factor. In one embodiment, the interfaces are used for different tasks (e.g., WLAN for data and PAN for human interface devices), and the device includes logic configured to evaluate the priority of the tasks and adjust the operation of one or more of the interfaces accordingly.

PRIORITY AND RELATED APPLICATIONS

This application claims priority to U.S. Provisional Patent ApplicationSer. No. 61/657,633, entitled “METHODS AND APPARATUS FOR MITIGATINGINTERFERENCE IN AGGRESSIVE FORM FACTOR DESIGNS”, filed Jun. 8, 2012,which is incorporated by reference herein in its entirety.

This application is related to co-pending U.S. patent application Ser.No. 13/025,059 filed Feb. 10, 2011 and entitled “METHODS AND APPARATUSFOR WIRELESS COEXISTENCE BASED ON TRANSCEIVER CHAIN EMPHASIS”, and U.S.patent application Ser. No. 13/312,894 filed Dec. 6, 2011 and entitled“METHODS AND APPARATUS FOR WIRELESS OPTIMIZATION BASED ON PLATFORMCONFIGURATION AND USE CASES”, each of the foregoing incorporated hereinby reference in its entirety.

COPYRIGHT

A portion of the disclosure of this patent document contains materialthat is subject to copyright protection. The copyright owner has noobjection to the facsimile reproduction by anyone of the patent documentor the patent disclosure, as it appears in the Patent and TrademarkOffice patent files or records, but otherwise reserves all copyrightrights whatsoever.

BACKGROUND

1. Technical Field

The present disclosure relates generally to the field of interferencemitigation within wireless networks. More particularly, in one exemplaryembodiment, the present disclosure is directed to mitigatinginterference between multiple radio interfaces in aggressive form factordesigns.

2. Description of Related Technology

The growing market for so-called “convergence products” has led to arevolution in the way consumers view computerized devices. These nextgeneration computerized devices focus on offering consumers asubstantially unified solution for a variety of services to whichconsumers have become accustomed. Common examples of such convergenceproducts include, but are not limited to laptop computers, smart phones,and tablet computers such as the exemplary iMac™, Mac-Mini™, Apple TV™,Mac Pro™, Macbook™, Macbook Pro™, Macbook Air™, iPhone™, and iPad™manufactured by the Assignee hereof. Convergence products must generallysupport a variety of wireless protocols and other functions. Forinstance, a convergence smart phone such as the iPhone has thecapability of, among other things, sending and receiving emails over aWireless Local Area Network (WLAN) such as e.g., the IEEE 802.11a/b/g/nstandards, making and receiving voice/data calls using a cellularnetwork (e.g., Global System for Mobile Communications (GSM), UniversalMobile Telecommunications System (UMTS), LTE or LTE-A, etc.) andoperating wireless peripheral equipment (such as wireless headsets,keyboards, etc.) using a personal area network (PAN) (e.g., Bluetooth™protocol (BT), etc.) and providing location services (e.g., via GlobalPositioning System (GPS)).

Within this context, aggressive form factor designs and new designparadigms have greatly altered the landscape of consumer electronics.Consumers demand design qualities that transcend functionality; certainqualities such as reduced size, aesthetic appeal, portability, sharedresources (e.g., multi-purposed components), and battery life have takenprecedence over traditional design criteria. For example, metallicconstruction is often highly desired; however, those of ordinary skillwill recognize that metallic materials can shield and/or interfere withradio reception. Similarly, compressing multiple radio transceiverswithin aggressively compact form factors contributes significantly tooverall platform noise and may create other co-existence issues.Moreover, consumer electronics must provide higher performance overlegacy platforms to satisfy evolving user expectations.

As devices have evolved according to customer preferences, certaindesign tradeoffs have adversely affected performance. Lower performancecan potentially result in a poor user experience with the device. Forexample, certain aggressive form factors implement both BT and WLANtransceivers/antennae within very close physical proximity to oneanother. Unfortunately, BT and WLAN share the same ISM (IndustrialScientific Medical) radio band; i.e., 2.4-2.48 GHz frequency range.Consequently, BT and WLAN technologies will often interfere with eachother when operating simultaneously, which causes noticeable problems inthe user interface (e.g., BT audio stutter and drop-outs, slow WLANtransfer speeds, poor BT mouse tracking, keyboard and touchpadperformance, or “jerkiness”, etc.) and in very severe conditions, canresult in link failures.

Current and future consumer electronics device manufacturers mustre-evaluate existing design assumptions. Future designs will need toestablish new schemes for handling aggressive form factor designs andnew design paradigms. In particular, new constraints (such as size andlayout, manufacturing and design cost, product schedules, etc.) must bebalanced against demands for high performance processors, memories,interfaces, system buses, display elements, and high rate clocking, etc.Realistically, future devices will have to tolerate higher platformnoise (e.g., both static and dynamic noise floors (NF)) while stilldelivering acceptable performance and user experience.

Accordingly, improved solutions are needed for mitigating interferencebetween multiple radio interfaces in, e.g., aggressive form factordesigns.

SUMMARY

The present disclosure provides, inter alfa, improved apparatus andmethods for mitigating interference between multiple radio interfaces inaggressive form factor designs.

In one respect, a wireless-enabled user device is disclosed. The deviceincludes a plurality of wireless interfaces, where one or more of thewireless interfaces that are configured to negotiate with one another todetermine the highest priority wireless interface. In one exemplaryvariant, a bus interface enables one or more data transfer protocolsbetween e.g., a wireless local area network (WLAN) baseband and aBluetooth (BT) baseband.

In another embodiment of the device, the physical isolationcharacteristics of the antennas of the wireless device are leveraged tooptimize the physical design of the device. Specifically, in oneembodiment, during initial design analysis, WLAN/BT antenna isolation ismeasured in both a so-called “open lid mode” (i.e., where the wirelessdevice has been opened for operation) and a so-called “clamshell mode”(i.e., where the wireless device is closed). Those of ordinary skill inthe related arts will readily appreciate that the physical configurationdoes not necessarily limit operation. For example, in open lid mode theuser can use the built-in keyboard, mouse and touchpad, whereas duringthe clamshell mode the user may use an external display, mouse, andkeyboard (i.e., the device is closed but still operating). Differentcoexistence schemes may be used for different physical and/oroperational configurations.

A non-transitory computer readable apparatus is also disclosed. Theapparatus includes one or more instructions that are configured to, whenexecuted, cause a processor to: control first and second wirelessinterface (e.g., WLAN and BT) transmit power. In one exemplary variant,the WLAN (processor) can adjust one or more WLAN transmit poweraccording to a tuple (such as a triplet) corresponding to differentantennas of a multiple-input-multiple-output (MIMO) array. The WLANbaseband can additionally instruct the BT baseband to boost transmitpower to e.g., prioritize BT traffic, improve BT performance, etc.

In another embodiment, the instructions are configured to limit certaintransactions to particular resources. For example, in one such variant,the WLAN processor can allocate a particular antenna for a specifiedtask and/or message; e.g., the WLAN baseband can dedicate an antenna foronly transmitting high priority signals.

In yet another aspect, an exemplary wireless device is configured withlogic that selectively turns off one or more radio or transmit/receivechannel components (or otherwise adjusts their use/behavior) based one.g., the level of interference.

Methods of minimizing co-existence interference in a wireless devicewith aggressive form factor are also disclosed.

In yet a further aspect, methods of enhancing WLAN data throughputwithout significantly impacting user experience are disclosed.

A wireless enabled user device is further disclosed. In one embodiment,the wireless enabled user device includes: a first wireless interfaceoperative in a first frequency band; a second wireless interfacedisposed proximate the first interface within the device and operativein a substantially overlapping frequency band with the first frequencyband; and logic in communication with at least one of the first andsecond interfaces. In one such example, the logic is configured to:determine at least one priority of concurrent first and second tasks tobe performed by the first and second interfaces, respectively; andadjust operation of at least one of the interfaces based on the at leastone determined priority so as to achieve at least one of: (i) mitigatedradio interference; and/or (ii) enhanced data throughput.

In one variant, the adjustment of the operation is based at least inpart on a first priority associated with the first wireless interface.For example, the first priority may be determined for the first wirelessinterface in response to a query from the first wireless interface.

In other variants, the adjustment of the operation includes a firstassignment of one or more first antennas to the first interface forcompletion of the first task.

In still other variants, the adjustment of the operation furtherincludes a second assignment of at least one second antenna to thesecond interface for completion of the second task, where the first andsecond antennas have a known isolation.

In some implementations, the adjustment of operation includes a delay incompletion of the first task.

In certain cases, the determined at least one priority is based on astatic priority scheme. In other cases, the determined at least onepriority is based at least in part on user input.

Still further, the determined at least one priority may include a firstpriority level associated with the first task and a second prioritylevel associated with the second task. In some cases, the user devicemay include logic configured to reserve at least one antenna for thefirst task assigned to the first priority level. Still otherimplementations may include where the first priority level is associatedwith human interface device (HID) operation and the second prioritylevel is associated with internet protocol (IP) activity, the firstpriority level being greater than the second priority level.

A wireless interface is also disclosed. In one embodiment, the wirelessinterface includes: a transmission device; and processing logic inoperative communication with the transmission device, the processinglogic configured to run one or more computer programs thereon. In oneexemplary embodiment, the one or more computer programs include aplurality of instructions configured to, when executed, cause thewireless interface to: query a priority logic, the priority logicconfigured to select a priority scheme associated with execution of oneor more tasks by the wireless interface; and based at least in part onthe selected priority scheme, adjust one or more operational parametersused in the execution of the one or more tasks; where the priorityscheme is selected to optimize data throughput of the wireless interfaceand at least one other wireless interface with overlapping spectralusage.

In one variant, the adjustment of the one or more operational parametersincludes adjustment of a transmit power of the transmission device.

In other variants, the transmission device includes a multiple-inputmultiple-output (MIMO) antenna array, and the adjustment of the transmitpower is based on a tuple of the MIMO antenna array.

In some implementations, the transmission device includes a plurality ofcomponents; and the adjustment of the one or more operational parametersincludes deactivation of at least one of the plurality of componentsduring execution of the one or more tasks.

A method of managing interference during operation of at least twowireless interfaces with overlapping spectral usage is furtherdisclosed. In one embodiment, the method includes: determining aplurality of priorities corresponding to a plurality of tasks that arescheduled to be simultaneously executed, the plurality of tasks beingassociated with respective ones of the at least two wireless interfaces;and based on the determined plurality of priorities, altering theexecution of at least one of the plurality of tasks; wherein the alteredexecution reduces a resource interference for the at least two wirelessinterfaces with overlapping spectral usage.

In some variants, the determining of at least a first priority includespolling a baseband processor for the priority.

In other variants, the altered execution includes adjusting a transmitpower associated with the at least one of the plurality of tasks.

A non-transitory computer-readable apparatus configured to store atleast one computer program thereon is also disclosed. In one embodiment,the computer program includes a plurality of instructions configured to,when executed cause a device to: identify a plurality of operations tobe performed by at least a first and a second wireless interfaces via atleast a first and a second resources, respectively; determine a priorityscheme for the plurality of operations; and based at least in part onthe priority scheme, manage the first and second resources, where thefirst and second resources interfere when operated concurrently; wherethe priority scheme is configured to avoid a concurrent use.

A wireless communication system is additionally disclosed. In oneembodiment, the wireless communication system includes: a first wirelesscommunication device configured to operate using a first protocol; asecond wireless communication device configured to operate using asecond protocol, the first and second protocols using overlappingspectral resources; and priority logic configured to manage a pluralityof concurrent operations on respective ones of the first and secondwireless communication devices; where the first wireless device isconfigured to, based at least on the priority logic, adjust one or moretransmission and/or reception parameters so as to reduce interferenceamong the plurality of concurrent operations.

Other features and advantages will immediately be recognized by personsof ordinary skill in the art with reference to the attached drawings anddetailed description of exemplary embodiments as given below.

BRIEF DESCRIPTION OF THE DRAWINGS

FIG. 1 is a logical block diagram of one exemplary prior art wirelesslocal area network/Bluetooth (WLAN/BT) client device.

FIG. 2 is a graphical representation of experimentally determinedperformance metrics for the exemplary prior art WLAN/BT client device ofFIG. 1.

FIG. 3 is a table of prior art WLAN/BT client device (of FIG. 1)performance for a set of common user tasks during concurrent operationof both WLAN and BT interfaces.

FIG. 4 is a graphical representation of the performance of the BT radioof the prior art client device of FIG. 1 into a saturation region.

FIG. 5 is a logical block diagram of one exemplary client device, inaccordance with various embodiments.

FIG. 6 is a graphical representation of a comparison of antennaisolation between the device of FIG. 5 and the prior art device of FIG.1.

FIG. 7 is a graphical representation of experimentally determinedperformance metrics for the exemplary WLAN/BT client device of FIG. 5.

FIG. 8 is a table of WLAN/BT client device (of FIG. 5) performance for aset of common user tasks during concurrent operation of both WLAN and BTinterfaces.

All Figures © Copyright 2012-2013 Apple Inc. All rights reserved.

DETAILED DESCRIPTION

Reference is now made to the drawings, wherein like numerals refer tolike parts throughout.

Detailed Description of Exemplary Embodiments

Exemplary embodiments are now described in detail. While theseembodiments are primarily discussed in the context of a device havingboth WLAN and Bluetooth wireless interfaces, the general principles andadvantages may be extended to other types of wireless devices thatexperience significant noise due to aggressive form factor design and/ordesigns that share a crowded transmission medium across multiple radiotechnologies resulting in reduced data rates, the following thereforebeing merely exemplary in nature.

For example, those of ordinary skill in the related arts will recognizethat various implementations are widely applicable to other wirelesstechnologies, especially those that are typically packaged with otherinterference-generating components (e.g., digital components such as acentral processing unit (CPU), graphics processor (GFX), memorycomponents, hard disk drives (HDD), liquid crystal displays (LCDs),other wireless interfaces, etc.). Such applications include for example,cellular applications, wireless personal media devices, and the like.

Overview

In one aspect, the aforementioned issues are addressed by, inter cilia,coordinated management of tasks on interfaces with overlapping spectralusage as disclosed herein. For example, in one embodiment, interfacesmay be used for different tasks (e.g., wireless local area network(WLAN) for data and personal area network (PAN) for human interfacedevices), and configured to evaluate the priority of the tasks andadjust the operation of one or more of the interfaces. Intelligentprioritization and/or adjustment can mitigate any coexistence problemsthat may occur.

In various implementations, the one or more coexisting wirelessinterfaces are configured to negotiate with one another to determine thehighest priority wireless interface. For example, the WLAN baseband maycoordinate priorities between itself and the PAN baseband via a mutualinterface.

In some cases, the negotiation between the interfaces (or management bydedicated logic) is based on task priorities. Certain tasks may beemphasized more than others. In other use cases, priorities may bedynamically altered or reconfigured, such as e.g., determined by ahigher level process or application.

In various implementations, the physical isolation characteristics ofthe antennas of the wireless device are leveraged to optimize thephysical design of the device. For example, during initial designanalysis, the WLAN/PAN antenna isolation may be measured according tomultiple operating mode scenarios; for each of the scenarios, theoperational parameters are optimized for each of the modes. In anotherexample, multiple antennas (e.g., an array or group, etc.) areimplemented with varying capabilities/performances depending on antennaassignment (e.g. broadcast power, received signal strength, isolation,modulation and coding, multiple-input multiple-output (MIMO) operation,etc.). As described in greater detail herein, intelligent management ofantenna resources can be used to maximize coexistence performance (e.g.user experience, throughput, etc.).

Existing Wireless Technology—

New products continue to push the limits of existing IEEE 802.11a/b/g/nand Bluetooth (BT) coexistence. Consider an exemplary mobile device withan IEEE 802.11 Wireless Local Area Network (WLAN) MIMO (multiple input,multiple output) 3×3 interface, and a BT interface, where the WLAN andBT interface share one or more antennas. Unfortunately, when theseradios are packed into an aggressive form factor design, the resultinginterference cannot meet existing performance requirements.

For example, the exemplary Macbook Pro (manufactured by the Assigneehereof) includes three (3) antennas in a clutch barrel (the hingeportion of the device contains springs that form a clutch mechanism,which is referred to as the so-called “clutch barrel”) and a so-called“retina” type display. The relatively small size of the clutch barreland close proximity to the high-speed display interface greatly impactsantenna isolation. The measured average isolation between antennas isvery low and greatly compromises antenna performance. Noticeable impactsof low isolation include, for example, BT mouse (MS) “skipping” and/or“jumpiness”, low WLAN throughput and/or data rates, erratic devicebehaviors, connection loss, etc. Furthermore, recent improvements in BTcomponents have added enhanced transmit modes that can boost transmitpower up to 10 dBm. If improperly managed, boosted BT operation canfurther jam or degrade WLAN operation.

Referring now to FIG. 1, one exemplary WLAN/BT capable client device 100is illustrated. As shown, one (1) antenna is shared between WLAN and BTvia a series of switches (WLAN #2/BT). The other two (2) antennas forWLAN (WLAN #1, WLAN #3) have limited isolation to the shared antenna(WLAN #2/BT). During certain operational modes, the WLAN and BTinterfaces “time share” or “time multiplex” the shared antenna. WLAN/BTtime sharing algorithms allocate a first portion of time to the BTinterface, and a second portion of time to the WLAN interface. Whiletypical BT devices use much lower data rates than the corresponding WLANinterface, the BT interface is typically higher priority, because mostBT devices are high-priority user interface type equipment (e.g., BTmouse, BT keyboard, BT headset (e.g., both Synchronous ConnectionOriented (SCO) mono and Advanced Audio Distribution Profile (A2DP)stereo implementations), etc.) which can directly impact userexperience. In fact, if the system of FIG. 1 is connected to several BTdevices, then WLAN transmit and receive performance is significantlyimpacted due to such BT prioritization. In some cases, when WLAN datarates drop below a certain level (e.g., lower than 10 Mbps), manydesirable applications can no longer be supported (e.g., High Definition(HD) video streaming, FacenTime™, etc.).

As a brief aside, within the exemplary context of IEEE 802.11n wirelessnetworks, a predefined set of Modulation and Coding Schemes (MCS) arerecognized by IEEE 802.11n-compliant devices; each MCS is uniquelyidentified by an index value. During operation, a transmitter determinesan appropriate MCS and transmits the corresponding index value to thereceiver. Responsively, the receiver configures itself according to theindex value. TABLE 1 below details extant Modulation and Coding Schemes(MCS) implemented within IEEE 802.11n compliant devices as of thepresent date.

TABLE 1 Data rate (Mbit/s) MCS Spatial Modulation Coding 20 MHz channel40 MHz channel index streams type rate 800 ns GI 400 ns GI 800 ns GI 400ns GI 0 1 BPSK ½ 6.50 7.20 13.50 15.00 1 1 QPSK ½ 13.00 14.40 27.0030.00 2 1 QPSK ¾ 19.50 21.70 40.50 45.00 3 1 16-QAM ½ 26.00 28.90 54.0060.00 4 1 16-QAM ¾ 39.00 43.30 81.00 90.00 5 1 64-QAM ⅔ 52.00 57.80108.00 120.00 6 1 64-QAM ¾ 58.50 65.00 121.50 135.00 7 1 64-QAM ⅚ 65.0072.20 135.00 150.00 8 2 BPSK ½ 13.00 14.40 27.00 30.00 9 2 QPSK ½ 26.0028.90 54.00 60.00 10 2 QPSK ¾ 39.00 43.30 81.00 90.00 11 2 16-QAM ½52.00 57.80 108.00 120.00 12 2 16-QAM ¾ 78.00 86.70 162.00 180.00 13 264-QAM ⅔ 104.00 115.60 216.00 240.00 14 2 64-QAM ¾ 117.00 130.00 243.00270.00 15 2 64-QAM ⅚ 130.00 144.40 270.00 300.00 16 3 BPSK ½ 19.50 21.7040.50 45.00 17 3 QPSK ½ 39.00 43.30 81.00 90.00 18 3 QPSK ¾ 58.50 65.00121.50 135.00 19 3 16-QAM ½ 78.00 86.70 162.00 180.00 20 3 16-QAM ¾117.00 130.70 243.00 270.00 21 3 64-QAM ⅔ 156.00 173.30 324.00 360.00 223 64-QAM ¾ 175.50 195.00 364.50 405.00 23 3 64-QAM ⅚ 195.00 216.70405.00 450.00 24 4 BPSK ½ 26.00 28.80 54.00 60.00 25 4 QPSK ½ 52.0057.60 108.00 120.00 26 4 QPSK ¾ 78.00 86.80 162.00 180.00 27 4 16-QAM ½104.00 115.60 216.00 240.00 28 4 16-QAM ¾ 156.00 173.20 324.00 360.00 294 64-QAM ⅔ 208.00 231.20 432.00 480.00 30 4 64-QAM ¾ 234.00 260.00486.00 540.00 31 4 64-QAM ⅚ 260.00 288.80 540.00 600.00For a 3×3 MIMO client, only MCSO through MCS23 are available (i.e., eachantenna can handle a spatial stream, so a 3×3 MIMO system can handlethree (3) spatial streams). During intervals of relatively high RSSI(e.g., presumably when the client device and the WLAN AP are very closein spatial proximity), prior art IEEE 802.11n transmitters will increasethe MCS complexity to take advantage of the clear channel conditions(e.g., the WLAN AP allocates a 3×3 MCS (e.g., MCS 21, 22, and 23 utilize64-QAM which requires a relatively high SNR)). Similarly, when channelquality has significantly degraded, the IEEE 802.11n transmitterswitches down to lower, more robust MCS configurations.

FIG. 2 is a graphical representation 200 of experimentally determinedperformance metrics for the exemplary WLAN/BT capable client device 100of FIG. 1 with a hybrid time sharing interference mitigation scheme. Inthis scenario, the client device (Macbook Pro® (MBP)) has turned on itsWLAN transmitter (e.g., Channel 6) while a BT mouse is placedapproximately thirty (30) centimeters (cm) away (a typical use casedistance) and rotated around the client device from −30 degrees to 210degrees, with measurements performed at 30 degree increments.Illustrative values for RSSI (receiver signal strength index) and packeterror rate (PER) are shown for clarity, although it is readilyappreciated by those of ordinary skill that actual measured values willvary widely based on e.g., component tolerances, radio conditions, etc.Within this context, it is of particular note that while the WLANtransmitter is active the BT mouse will experience PER that exceeds 30%;this relatively high PER results in “jerky” mouse operation, which isundesirable from a consumer standpoint.

FIG. 3 presents a summary 300 of client device performance for a set ofcommon user tasks during concurrent operation of both WLAN and BTinterfaces. Many of the target usage scenarios show some degree ofperceptible impairment, and certain use cases fail altogether.

Furthermore, FIG. 4 is a graphical illustration 400 of some fundamentalissues with poor isolation. As shown, the graph presents the input powerto the BT radio and the resulting received signal strength (RSS) asmeasured at the BT radio. As shown, the graph “levels out”, due tosaturation of the radio components.

Within this context, assuming that the WLAN and BT radios haveapproximately 15 dB of isolation, if the WLAN radio transmits at anintegrated power of 18 dBm/20 MHz this translates to approximately 13 dBof noise for the BT radio. Specifically, BT uses a 1 MHz bandwidth whichcorresponds to 1/20^(th) of the WLAN bandwidth. This results in a lossfactor of 20 which is equivalent to a −13 dB attenuation. Consequently,the BT radio only receives a maximum power of 5 dBm/MHz (18 dBm/20MHz−13 dB=5 dBm/MHz); with only a 15 dB isolation, the BT radio willreceive approximately −10 dBm (5 dBm/MHz−dB=−10 dBm). This receive powerwill saturate the BT radio. Similarly, if the BT radio transmits at 10dBm/MHz, then with 15 dB isolation, the WLAN radio will receiveapproximately −5 dBm (10 dBin/MHz−15 dB=−5 dBm).

In view of the foregoing complications, improved methods and apparatusfor mitigating interference between multiple radio interfaces areneeded. Ideally, such improved methods and apparatus should reduce bothin-band noise and out of band noise within very aggressive form factors.In particular, these solutions should handle scenarios with low orlimited radio isolation characterized by: blocking/compression of RFsignaling, undesirable inter-modulation (IM) products, increased noisefloors, distortions/non-linearities, etc. Still further, such solutionsmay further reduce unexpected interferences such as e.g., improperlydesigned filters, out of tolerance components, etc.

Exemplary Apparatus—

Various embodiments are now described in greater detail. In oneembodiment, the wireless device includes at least a first radio and asecond radio, where the first and second radios interfere to at leastsome degree with one another. In one implementation, the first radioincludes Wireless Local Area Network (WLAN) interface such as IEEE802.11-compliant Iii-Fi, and the second radio includes a Personal AreaNetwork (PAN) such as e.g., Bluetooth.

Exemplary Hardware Apparatus—

Referring now to FIG. 5, one logical block representation of thewireless device 500 configured to mitigate interference between multipleradio interfaces in aggressive form factor designs is presented. As usedherein, the term “wireless device” includes, but is not limited tocellular telephones, smart phones (such as for example an iPhone™manufactured by the Assignee hereof), handheld computers, tabletdevices, personal media devices (PMDs), or any combinations of theforegoing. While a specific device configuration and layout is shown anddiscussed, it is recognized that many other implementations may bereadily implemented by one of ordinary skill given the presentdisclosure, the wireless device 500 of FIG. 5 being merely illustrativeof the broader principles disclosed herein.

The processing subsystem 502 includes one or more of central processingunits (CPU) or digital processors, such as a microprocessor, digitalsignal processor, field-programmable gate array, RISC core, a basebandprocessor, or plurality of processing components mounted on one or moresubstrates. In some embodiments, one or more of the above-mentionedprocessors (e.g. the baseband processor) are further configured toexecute one or more processor instructions stored on a non-transitorycomputer-readable storage media 504.

As shown, the processing subsystem is coupled to non-transitorycomputer-readable storage media such as memory 504, which may includefor example SRAM, FLASH, SDRAM, and/or HDD (Hard Disk Drive) components.As used herein, the term “memory” includes any type of integratedcircuit or other storage device adapted for storing digital dataincluding, without limitation, ROM. PROM, EEPROM, DRAM, SDRAM, DDR/2SDRAM, EDO/FPMS, RLDRAM, SRAM, “flash” memory (e.g., NAND/NOR), andPSRAM. The processing subsystem may also include additionalco-processors, such as a dedicated graphics accelerator, networkprocessor (NP), or audio/video processor. As shown processing subsystem502 includes discrete components; however, it is understood that in someembodiments they may be consolidated or fashioned in a SoC(system-on-chip) configuration.

The wireless device 500 further includes one or more wireless interfaces506 as discussed above. For example, in one exemplary implementation,the wireless device includes a WLAN baseband modem 506A (compliant withIEEE 802.11 wireless standards, e.g., Wi-Fi) and a Bluetooth (BT)baseband modem 506B. In the illustrated device 500, the WLAN interface(CH0, CH1, CH2) has two (2) antennas 508B (ANT1), 508C (ANT2) and sharesan antenna 508A (ANT0) with the BT interface via a switch element 510.During certain operational modes, the WLAN and BT interfaces “timeshare” the shared antenna. Specifically, WLAN/BT time sharing algorithmsallocate a first portion of time to the BT interface, and a secondportion of time to the WLAN interface.

In one salient embodiment, the one or more wireless interfaces areconfigured to negotiate with one another to determine the highestpriority wireless interface. In one configuration, the WLAN baseband506A coordinates priorities between itself and the BT baseband 506B viaa bus interface 512. Common examples of a bus interface include forexample: address and data busses, serial interfaces, parallelinterfaces, etc. Specifically, in one exemplary variant, the businterface enables a data transfer protocols between the WLAN basebandand the BT baseband.

The WLAN baseband 506A can also be configured to allocate or grant oneor more resources for the BT traffic based on priority information. Insome variants, the WLAN baseband may poll or query the BT baseband todetermine the BT traffic priority information. In alternate embodiments,the BT baseband may request one or more resources to support BT traffic.As used herein, the term “resources” refers generally and withoutlimitation physical or logical elements which are useful for supportingwireless operation and which are limited in availability. Commonexamples of resources include e.g., antennas, time slots, spectralresources, orthogonal spreading codes, time-frequency resources, etc.

Once the WLAN baseband has determined the BT traffic priorityinformation, the WLAN baseband assigns a priority to each portion ofWLAN traffic and BT traffic. In one embodiment, priorities are assignedbased on data type. For example, in one such scheme, priorities areassigned to each of WLAN/BT scanning procedures, control flow packets(such as acknowledgments (ACK), etc.), BT human interface devices (HID)(such as mouse, keyboard, touchpad, etc.), audio data, and WLAN and BTdata packets. Based on the relative priority of the traffic type, theWLAN baseband assigns resources accordingly. For example, the WLANbaseband identifies that BT traffic is of a higher priority than theWLAN traffic; accordingly, the WLAN baseband dedicates the BT traffic tothe shared antenna, and scales its own traffic for the remaining two (2)antennas. Once the BT traffic priority has dropped, the WLAN basebandcan switch the shared antenna back to a time shared hybrid mode.

It will be appreciated that while an exemplary implementation of thedevice 500 utilizes a static or predetermined prioritization scheme inthe foregoing scheme (e.g., mouse use is prioritized over WLAN use), inother implementations the priorities may be dynamically altered orreconfigured. For instance, in some embodiments the prioritizationscheme may be determined by a higher level process or softwareapplication (e.g., running on the device processor) which evaluates thecurrent operational environment/status of the device 500 and makes aprioritization based thereon, according to e.g., user input,preferences, context (e.g., “work” versus “personal” use), an externalentity requirements (e.g., a Wi-Fi AP or BT master device to which theBT interface of the device 500 is slaved), etc.

In various implementations, the physical isolation characteristics ofthe antennas of the wireless device are leveraged to optimize thephysical design of the device. Specifically, during initial designanalysis, the WLAN/BT antenna isolation is measured in both in aso-called “open mode” (i.e., where the lid has been opened for use as ine.g., a laptop) and a so-called “clamshell mode” (i.e., where the lid isclosed, but one or more wireless interfaces are still active). In oneexemplary embodiment, the WLAN baseband 506A and BT baseband 506B areconnected to antennas 508A, 508B, and 508C. While the WLAN baseband isconnected to all three (3) antennas the BT baseband experiencesdifferent degrees of performance based on which antenna it is connectedto, thus by intelligently selecting the appropriate antenna, BTperformance can be improved significantly.

Referring now to FIG. 6, performance measurements for the BT basebandaccording to the exemplary prior art device 100 (FIG. 1) compared to theexemplary device 500 (FIG. 5) are shown. The BT RSST is measuredaccording to a so-called “sweep” from Channel 0 to 78. During the sweepmeasurement, the WLAN is configured to transmit via one or more of itstransmit chains (CH0, CH1, CH2) with its highest transmit power at afixed frequency (e.g., Channel 6) over one or more of the antennas 508A,508B, and 508C, while the BT baseband measures the noise floor (NF).

A first performance chart illustrates the overall isolation (WLANtransmitting on all chains over all antennas) 600 as determined by theBT baseband on antenna 508B (602), compared to the BT baseband connectedto antenna 508A (604).

A second performance chart 610 illustrates the comparison for isolationbetween WLAN transmitting on CH0 over antenna 508B versus BT on antenna508B (612) and BT on antenna 508A (614).

A third performance chart 620 illustrates the comparison for isolationbetween WLAN transmitting on CH1 over antenna 508A versus BT on antenna508B (622) and BT on antenna 508A (624) (as shown the isolation isdominated by the RF switch isolation.

A fourth performance chart 630 illustrates the comparison for isolationbetween WLAN transmitting on CH2 over antenna 508C versus BT on antenna508B (622) and BT on antenna 508A (624).

Techniques and architectures for mitigating mutual interference for suchco-located wireless transmitters are presented in co-owned andco-pending U.S. patent application Ser. No. 13/025,059 filed Feb. 10,2011 and entitled “METHODS AND APPARATUS FOR WIRELESS COEXISTENCE BASEDON TRANSCEIVER CHAIN EMPHASIS”, previously incorporated herein byreference in its entirety. As discussed therein, methods and apparatusfor mitigating the effects of radio frequency (RF) interference betweenco-located or proximate wireless devices in a client or user device suchas a mobile computer or smartphone as disclosed. In one exemplaryembodiment, the methods and apparatus dynamically mitigate theinterference between co-located WLAN/PAN air interfaces disposed withina physically constrained device by adjusting one or more parametersspecific to each transmit “chain”. For example, each transmit chain ofthe WLAN can be calibrated to a specific transmit power, where thecalibrated transmit power is configured to minimize interference withthe nearby but unrelated PAN.

Exemplary Software—

Referring back to FIG. 5, in one embodiment, the non-transitorycomputer-readable storage media 504 further includes instructions thatcan be executed by at least one of the processing subsystem 502, theWLAN baseband processor 506A and/or the BT baseband processor 506B.

In various implementations, one or more instructions of thenon-transitory computer-readable storage media are configured to controlat least one of WLAN and BT transmit power. In one exemplary embodiment,the WLAN processor can adjust one or more WLAN transmit powers accordingto a so-called “tuple” such as a triplet (e.g., [−x dBm, −y dBm, −zdBm], where the elements of the triplet correspond to the antennas 508A,508B, 508C). In one such variant, the WLAN baseband can additionallyinstruct the BT baseband to boost transmit power to e.g., prioritize BTtraffic, improve BT performance, etc. Responsively, the BT basebandincreases its corresponding transmit power from e.g., 0 dBm to 10 dBmwhen so instructed.

For example, consider a WLAN baseband processor which is configured toadjust at least one of WLAN and BT transmit power according tonegotiated priorities. As previously alluded to, the WLAN baseband 506Acan coordinate priorities between itself and the BT baseband 506B viathe bus interface 512. Based on the relative priority of the traffic,the WLAN baseband can assign and/or determine an appropriate transmitpower. For example, when the WLAN baseband identifies that BT traffic isof a higher priority than the WLAN traffic, the WLAN baseband instructsthe BT baseband to boost its (the BT transmitter's) transmit power limitto 10 dBm. Once the BT traffic priority has dropped, the BT baseband canrevert back to the lower transmit power limit (e.g., 0 dBm). In somevariants, the WLAN baseband processor provides one or more instructionsto the BT baseband over the bus interface 512.

In various implementations, one or more instructions of thenon-transitory computer-readable storage media are configured to limitcertain transaction to particular resources. For example, in one suchembodiment, the WLAN processor can allocate a particular antenna for aspecified task and/or message; e.g., the WLAN baseband can dedicate anantenna for only transmitting high priority signals (such as e.g.,control flow messages). As a brief aside, control flow messages (such asresource grants, resource allocations, acknowledgements,non-acknowledgements, etc.) may be prioritized over normal data traffic,because control flow messages significantly affect network operation forthe device, the network, and other neighboring devices. By reserving asingle input single output (SISO) antenna configuration for transmittinge.g., ACK signaling (on the antenna with the best antenna isolation),the WLAN baseband is improving the likelihood of a successful ACKtransmission.

In a related embodiment, the WLAN baseband can (based on e.g., a certainamount of BT bandwidth, BT priority, etc.) direct the switching element510 to couple either the BT baseband or the WLAN baseband to the sharedantenna 508C. For example, consider a scenario where the BT baseband hasa large amount of high priority traffic; the WLAN baseband can switchthe shared antenna wholly to BT traffic. After the BT traffic, the WLANbaseband can reconfigure the switching element so as to support thetime-shared hybrid mode (which may incorporate various “fairness” orother allocation protocols).

Moreover, it should further be appreciated that in certain scenarios,the WLAN baseband will actually perform better on the remaining two (2)antennas when compared to time sharing the third antenna. For example,as disclosed within U.S. patent application Ser. No. 13/312,894 filedDec. 6, 2011 and entitled “METHODS AND APPARATUS FOR WIRELESSOPTIMIZATION BASED ON PLATFORM CONFIGURATION AND USE CASES”, (previouslyincorporated by reference in its entirety), the wireless device canprovide the wireless network with an indications of impacted operationsbased on the device's platform configuration. In this example, the WLANnetwork server (Access Point (AP)) can adjust the radio link WLAN devicefor fewer available antennas, rather than assigning a higher ordermodulation and coding scheme (MCS) scheme that the device cannot support(resulting in high failure rates).

In still another embodiment, the WLAN baseband can (based on e.g., acertain amount of BT bandwidth, BT priority, etc.) provide fartherlimitations to the BT baseband operations. In one such exemplaryembodiment, the WLAN baseband can instruct the BT baseband to limitautomatic frequency hopping procedures (AFH) under certain conditions.Unfortunately, when the WLAN baseband is transmitting at 2.4 GHz, the BTbaseband cannot detect the resulting interference in real time.Consequently, the WLAN baseband identifies one or more channels whichwill be will be heavily impacted by WLAN activity, and provides thisinformation to the BT baseband; responsively, the BT baseband cansignificantly improve AFH performance by avoiding the impacted channels.For example, when WLAN is transmitting in Channel 6, the WLAN basebandwill instruct the BT baseband to avoid operation in its 22 MHz main lobeand 18 MHz side lobes. The BT baseband will consider avoiding theseportions by e.g., performing AFH in the remaining thirty (30) channels.

Exemplary Wireless Interfaces—

Referring back to FIG. 5, in one implementation, the wireless interfaces506 are further configured to adjust component operation so as toprevent saturation effects.

As a brief aside, the exemplary wireless interfaces include variousanalog and feedback elements. Common examples of such components includefor example: automatic gain control (AGC), low noise amplifiers (LNA),automatic frequency control (AFC), analog to digital converters (A/D),digital to analog converters (D/A), etc. Generally, these components arehandled within discrete logic, and may be grossly controlled by theprocessor (if at all).

In one exemplary embodiment, the WLAN baseband is configured to turn onor off one or more components, depending on a degree of interference.For example, in one variant, the antenna includes a first LNA and asecond LNA (external LNA (eLNA)). Depending on the strength ofinterference, the WLAN baseband can disable the eLNA. Specifically, whenthe received signal strength (RSS) exceeds a maximum threshold, thereceived signal will saturate the A/D of the receiver. By disabling theeLNA, the received signal can be reproduced with better linearity,resulting in increased overall performance.

In one variant, the enabling and/or disabling of the eLNA is dynamicallycontrolled such that the eLNA is only disabled when the RSS issufficiently high. This ensures that the WLAN range is likelyunaffected. Furthermore, those of ordinary skill in the related artswill recognize that embodiments which have a larger number of LNAs canprogressively enable or disable LNAs, based on the overall RSS. Stillfurther, since LNAs provide various gain characteristics, in certaincircumstances LNAs may be selected intelligently for enabling/disablingbased on characteristics such as e.g., linearity, amount of gain, addednoise figure, etc.

In a further embodiment, the WLAN baseband is configured to re-tunevarious radio frequency (RF) components such that they are moreresilient to interference. Re-tuning may result in an increase tochannel-to-channel variability over the entire spectral range;therefore, in some cases certain performance tradeoffs may be necessaryso as to preserve e.g., performance, reliability, responsiveness, etc.For example, one common instance of re-tuning may include e.g., changingone or more filter characteristics. Filter characteristics can beadjusted to accentuate frequencies of interest, and/or attenuatefrequencies of interferers.

In still other embodiments, the WLAN baseband may instruct the BTbaseband to de-sense the BT components to prevent saturation by e.g.,disabling LNAs, adjusting RF components, etc. In alternate embodiments,the BT baseband may handle de-sense operations distinctly orindependently, or based on certain system inputs received from the WLANbaseband.

FIG. 7 is a graphical representation 700 of experimentally determinedperformance metrics for the exemplary WLAN/BT capable client device 500according to various implementations. In this scenario, the clientdevice (Macbook Pro (MBP)) has turned on its WLAN transmitter (e.g.,Channel 6) while a BT mouse is placed approximately thirty (30)centimeters (cm) away (a typical use case distance) and rotated aroundthe client device from −30 degrees to 210 degrees, with measurementsperformed at 30 degree increments. Illustrative values for RSSI(receiver signal strength index) and packet error rate (PER) are shownfor clarity, although it is readily appreciated by those of ordinaryskill that actual measured values will vary widely based on e.g.,component tolerances, radio conditions, etc. When contrasted to theresults of FIG. 2, it is readily apparent that performance of the clientdevice 500 have improved significantly.

FIG. 8 presents a summary 800 of the exemplary client device's 500performance for a set of common user tasks during concurrent operationof both WLAN and BT interfaces. As illustrated, significant improvementsin overall use scenario operation should be apparent (especially whenviewed in comparison to the results of FIG. 3).

It will be recognized that while certain embodiments are described interms of a specific sequence of steps of a method, these descriptionsare only illustrative of the broader methods in the disclosure, and maybe modified as required by the particular application. Certain steps maybe rendered unnecessary or optional under certain circumstances.Additionally, certain steps or functionality may be added to thedisclosed embodiments, or the order of performance of two or more stepspermuted. All such variations are considered to be encompassed withindisclosure and claims herein.

While the above detailed description has shown, described, and pointedout novel features as applied to various embodiments, it will beunderstood that various omissions, substitutions, and changes in theform and details of the device or process illustrated may be made bythose skilled in the art without departing from the disclosure. Theforegoing description is of the best mode presently contemplated ofcarrying out the principles disclosed herein. This description is in noway meant to be limiting, but rather should be taken as illustrative ofthe general principles of the disclosure. The scope should be determinedwith reference to the claims.

What is claimed is:
 1. A wireless enabled user device comprising: afirst wireless interface operative in a first frequency band; a secondwireless interface disposed proximate the first interface within thedevice and operative in a substantially overlapping frequency band withthe first frequency band; and logic in communication with at least oneof the first and second interfaces, the logic configured to: determineat least one priority of concurrent first and second tasks to beperformed by the first and second interfaces, respectively; and adjustoperation of at least one of the interfaces based on the at least onedetermined priority so as to achieve at least one of: (i) mitigatedradio interference; and/or (ii) enhanced data throughput.
 2. The userdevice of claim 1, wherein the adjustment of the operation is based atleast in part on a first priority associated with the first wirelessinterface.
 3. The user device of claim 2, wherein the first priorityassociated with the first wireless interface is determined in responseto a query from the first wireless interface.
 4. The user device ofclaim 1, wherein the adjustment of the operation comprises a firstassignment of one or more first antennas to the first interface forcompletion of the first task.
 5. The user device of claim 4, wherein theadjustment of the operation further comprises a second assignment of atleast one second antenna to the second interface for completion of thesecond task, where the first and second antennas have a known isolation.6. The user device of claim 1, wherein the adjustment of the operationcomprises a delay in completion of the first task.
 7. The user device ofclaim 1, wherein the determined at least one priority is based on astatic priority scheme.
 8. The user device of claim 1, wherein thedetermined at least one priority is based at least in part on userinput.
 9. The user device of claim 1, wherein the determined at leastone priority comprises a first priority level associated with the firsttask and a second priority level associated with the second task. 10.The user device of claim 9, further comprising logic configured toreserve at least one antenna for the first task assigned to the firstpriority level.
 11. The user device of claim 9, wherein the firstpriority level is associated with human interface device (HID) operationand the second priority level is associated with Internet Protocol (IP)activity, the first priority level being greater than the secondpriority level.
 12. A wireless interface comprising: a transmissiondevice; and processing logic in operative communication with thetransmission device, the processing logic configured to run one or morecomputer programs thereon, the one or more computer programs comprisinga plurality of instructions configured to, when executed, cause thewireless interface to: query priority logic, the priority logicconfigured to select a priority scheme associated with execution of oneor more tasks by the wireless interface; and based at least in part onthe selected priority scheme, adjust one or more operational parametersused in the execution of the one or more tasks; where the priorityscheme is selected to optimize data throughput of the wireless interfaceand at least one other wireless interface with overlapping spectralusage.
 13. The wireless interface of claim 12, wherein the adjustment ofthe one or more operational parameters comprises adjustment of atransmit power of the transmission device.
 14. The wireless interface ofclaim 13, wherein the transmission device comprises a multiple-inputmultiple-output (MIMO) antenna array, and the adjustment of the transmitpower is based on a tuple of the MIMO antenna array.
 15. The wirelessinterface of claim 12, wherein: the transmission device comprises aplurality of components; and the adjustment of the one or moreoperational parameters comprises deactivation of at least one of theplurality of components during execution of the one or more tasks.
 16. Amethod of managing interference during operation of at least twowireless interfaces with overlapping spectral usage, the methodcomprising: determining a plurality of priorities corresponding to aplurality of tasks that are scheduled to be simultaneously executed, theplurality of tasks being associated with respective ones of the at leasttwo wireless interfaces; and based on the determined plurality ofpriorities, altering the execution of at least one of the plurality oftasks; wherein the altered execution reduces a resource interference forthe at least two wireless interfaces with overlapping spectral usage.17. The method of claim 16, wherein the determining of at least a firstpriority comprises polling a baseband processor for the priority. 18.The method of claim 16, wherein the altered execution comprisesadjusting a transmit power associated with the at least one of theplurality of tasks.
 19. A non-transitory computer-readable apparatusconfigured to store at least one computer program thereon, the computerprogram comprising a plurality of instructions configured to, whenexecuted, cause a device to: identify a plurality of operations to beperformed by at least a first and a second wireless interfaces via atleast a first and a second resources, respectively; determine a priorityscheme for the plurality of operations; and based at least in part onthe priority scheme, manage the first and second resources, where thefirst and second resources interfere when operated concurrently; wherethe priority scheme is configured to avoid a concurrent use.
 20. Awireless communication system comprising; a first wireless communicationdevice configured to operate using a first protocol; a second wirelesscommunication device configured to operate using a second protocol, thefirst and second protocols using overlapping spectral resources; andpriority logic configured to manage a plurality of concurrent operationson respective ones of the first and second wireless communicationdevices; where the first wireless device is configured to, based atleast on the priority logic, adjust one or more transmission parametersso as to reduce interference among the plurality of concurrentoperations.